/***
 * Copyright 2002-2010 jamod development team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ***/

package net.wimpi.modbus.net;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.io.ModbusUDPTransport;

/**
 * Class implementing a <tt>UDPMasterTerminal</tt>.
 * 
 * @author Dieter Wimberger
 * @version @version@ (@date@)
 */
class UDPMasterTerminal implements UDPTerminal {

	private DatagramSocket m_Socket;
	private int m_Timeout = Modbus.DEFAULT_TIMEOUT;
	private boolean m_Active;
	protected InetAddress m_LocalAddress;
	protected InetAddress m_RemoteAddress;
	private int m_RemotePort = Modbus.DEFAULT_PORT;
	private int m_LocalPort = Modbus.DEFAULT_PORT;
	protected ModbusUDPTransport m_ModbusTransport;

	public UDPMasterTerminal() {
	}// constructor

	protected UDPMasterTerminal(InetAddress addr) {
		m_RemoteAddress = addr;
	}// constructor

	public InetAddress getLocalAddress() {
		return m_LocalAddress;
	}// getLocalAddress

	public void setLocalAddress(InetAddress addr) {
		m_LocalAddress = addr;
	}// setLocalAddress

	public int getLocalPort() {
		return m_LocalPort;
	}// getLocalPort

	protected void setLocalPort(int port) {
		m_LocalPort = port;
	}// setLocalPort

	/**
	 * Returns the destination port of this <tt>UDPSlaveTerminal</tt>.
	 * 
	 * @return the port number as <tt>int</tt>.
	 */
	public int getRemotePort() {
		return m_RemotePort;
	}// getDestinationPort

	/**
	 * Sets the destination port of this <tt>UDPSlaveTerminal</tt>. The default
	 * is defined as <tt>Modbus.DEFAULT_PORT</tt>.
	 * 
	 * @param port
	 *            the port number as <tt>int</tt>.
	 */
	public void setRemotePort(int port) {
		m_RemotePort = port;
	}// setPort

	/**
	 * Returns the destination <tt>InetAddress</tt> of this
	 * <tt>UDPSlaveTerminal</tt>.
	 * 
	 * @return the destination address as <tt>InetAddress</tt>.
	 */
	public InetAddress getRemoteAddress() {
		return m_RemoteAddress;
	}// getAddress

	/**
	 * Sets the destination <tt>InetAddress</tt> of this
	 * <tt>UDPSlaveTerminal</tt>.
	 * 
	 * @param adr
	 *            the destination address as <tt>InetAddress</tt>.
	 */
	public void setRemoteAddress(InetAddress adr) {
		m_RemoteAddress = adr;
	}// setAddress

	/**
	 * Tests if this <tt>UDPSlaveTerminal</tt> is active.
	 * 
	 * @return <tt>true</tt> if active, <tt>false</tt> otherwise.
	 */
	public boolean isActive() {
		return m_Active;
	}// isActive

	/**
	 * Activate this <tt>UDPTerminal</tt>.
	 * 
	 * @throws Exception
	 *             if there is a network failure.
	 */
	public synchronized void activate() throws Exception {
		if (!isActive()) {
			if (Modbus.debug)
				System.out.println("UDPMasterTerminal::activate()::laddr=:"
						+ m_LocalAddress + ":lport=" + m_LocalPort);
			if (m_Socket == null) {
				if (m_LocalAddress != null && m_LocalPort != -1) {
					m_Socket = new DatagramSocket(m_LocalPort, m_LocalAddress);
				} else {
					m_Socket = new DatagramSocket();
					m_LocalPort = m_Socket.getLocalPort();
					m_LocalAddress = m_Socket.getLocalAddress();
				}
			}
			if (Modbus.debug)
				System.out.println("UDPMasterTerminal::haveSocket():"
						+ m_Socket.toString());
			if (Modbus.debug)
				System.out.println("UDPMasterTerminal::laddr=:"
						+ m_LocalAddress.toString() + ":lport=" + m_LocalPort);
			if (Modbus.debug)
				System.out
						.println("UDPMasterTerminal::raddr=:"
								+ m_RemoteAddress.toString() + ":rport="
								+ m_RemotePort);

			m_Socket.setReceiveBufferSize(1024);
			m_Socket.setSendBufferSize(1024);

			m_ModbusTransport = new ModbusUDPTransport(this);
			m_Active = true;
		}
		if (Modbus.debug)
			System.out.println("UDPMasterTerminal::activated");
	}// activate

	/**
	 * Deactivates this <tt>UDPSlaveTerminal</tt>.
	 */
	public void deactivate() {
		try {
			if (Modbus.debug)
				System.out.println("UDPMasterTerminal::deactivate()");
			// close socket
			m_Socket.close();
			m_ModbusTransport = null;
			m_Active = false;
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}// deactivate

	/**
	 * Returns the <tt>ModbusTransport</tt> associated with this
	 * <tt>TCPMasterConnection</tt>.
	 * 
	 * @return the connection's <tt>ModbusTransport</tt>.
	 */
	public ModbusUDPTransport getModbusTransport() {
		return m_ModbusTransport;
	}// getModbusTransport

	/**
	 * Returns the timeout for this <tt>UDPMasterTerminal</tt>.
	 * 
	 * @return the timeout as <tt>int</tt>.
	 */
	public int getTimeout() {
		return m_Timeout;
	}// getReceiveTimeout

	/**
	 * Sets the timeout for this <tt>UDPMasterTerminal</tt>.
	 * 
	 * @param timeout
	 *            the timeout as <tt>int</tt>.
	 */
	public void setTimeout(int timeout) {
		m_Timeout = timeout;
	}// setReceiveTimeout

	public void sendMessage(byte[] msg) throws Exception {

		DatagramPacket req = new DatagramPacket(msg, msg.length,
				m_RemoteAddress, m_RemotePort);
		synchronized (m_Socket) {
			m_Socket.send(req);
		}
	}// sendPackage

	public byte[] receiveMessage() throws Exception {

		// 1. Prepare buffer and receive package
		byte[] buffer = new byte[256];// max size
		DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
		synchronized (m_Socket) {
			m_Socket.setSoTimeout(m_Timeout);
			m_Socket.receive(packet);
		}
		return buffer;
	}// receiveMessage

	public void receiveMessage(byte[] buffer) throws Exception {
		DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
		m_Socket.setSoTimeout(m_Timeout);
		m_Socket.receive(packet);
	}// receiveMessage

}// class UDPMasterTerminal
